The discovery of specimens of Tylopilus subg. Roseoscarbra in Australia prompted a comparative study of similar specimens from China, Japan, Costa Rica, and Eastern North America. The subgenus apparently originated in Laurasia. Populations of the subgenus migrated southwards from eastern Asia with their ectomycorrhizal hosts during Miocene/Pleistocene glaciations and subsequently adapted to different hosts in north-eastern Australia. The divergence in Australia is recognised in the new species: T. subchromapes, T. palumanus, T. queenslandianus, and T. propriorichromapes. Northern hemisphere populations disjuncted by the formation of the Atlantic Ocean are now recognised as new species in China — T. chlorinosmus, T. chromoreticulatus, and T. pinophilus — and in Japan, T. hongoi. During Pleistocene glaciation North American populations may have diverged in North and Central America that are recognised in Central America as T. cartagoensis and in North America as T. chromapes.
Two new species of Symplocos based on endocarps from the early Miocene Brandon Lignite of Vermont, USA